Various metal oxides are known as catalysts for numerous chemical reactions. One family of such metal oxides are those having the general formula ABO.sub.3 and that have the perovskite structure. Perovskites of course have been known for a number of decades and have been shown to have superconducting, ferromagnetic or ferroelectric properties. In addition to the stoichiometric perovskites, there are oxides that have structures derived from the perovskite structure. One category comprises non-stoichiometric compositions such as ABO.sub.3-x where the point defects are ordered in a specific manner to produce perovskite superstructures. Examples of these are Ca.sub.2 FeAlO.sub.5 and YBa.sub.2 Cu.sub.3 o.sub.7. The second category of perovskite-derivative structures are those that contain two-dimensional perovskite layers of composition A.sub.n-1 B.sub.n O.sub.3n+1 as one of the units building the layered structure. Another series of layered perovskites has the formula A'[A.sub.n-1 B.sub.n O.sub.3n+1 ] where A' is K, Rb or Cs. One member of this series is Cs Ca.sub.2 Nb.sub.3 O.sub.10.
The layered perovskite type oxides are interesting because of the potential to carry out chemistry between the layers. References to layered perovskite oxides include: Chem. Mater., 6, 907-912 (1994) which discloses an anion-deficient layered perovskite with a formula of ACa.sub.2 Nb.sub.3-x M.sub.x O.sub.10-x ; J. Mater. Chem. 3(7), 709-713(1993) which discloses layered oxides having a formula of A.sub.2-x La.sub.2 Ti.sub.3-x Nb.sub.x O.sub.10 ; J. Phys. Chem., 97, 1970-1973 (1993), which discloses a niobate layered perovskite having the formula ALaSrNb.sub.2 M.sup.11 O.sub.9.
All of the above described perovskites are prepared by solid state high temperature reaction and consequently have very low surface areas. In order for these perovskite type oxides to have greater widespread utility, it is important to synthesize layered compositions with large surface areas. There are reports of the synthesis of high surface area oxides with the pyrochlore structure. These are: U.S. Pat. No. 5,015,461 which discloses the synthesis of an oxide having the formula A.sub.2 B.sub.2 O.sub.7 where A is a divalent cation and B is niobium and/or tantalum and has the pyrochlore structure and Mat. Res. Bull., 27, 981-988 (1992) disclosing the synthesis of calcium-niobium and tantalum oxides with the pyrochlore structure and high surface area. Finally, U.S. Pat. No. 4,980,333 discloses a layered perovskite containing interspathic polymeric oxides between the layers. These polymeric oxides prop up the layers thereby increasing its surface area.
In contrast to the above art, applicant has synthesized metal oxide compositions having a triple layered perovskite structure and a high surface area (at least 30 m.sup.2 /g) and an empirical formula of: EQU AB.sub.2 M.sub.3 O.sub.10-x
where A is a monovalent exchangeable cation, B is at least one metal ion having a valence of +2 or +3, M is at least one metal ion having a valence of +2, +3, +4 or +5 and "x" has a value from about 0 to about 1. It is also important to note that unlike U.S. Pat. No. 4,980,333, applicant's compositions do not contain any pillars or interspathic polymeric oxides between the layers.